青海省祁漫塔格—都兰成矿带是以铁铜多金属为主的成矿带,其矿产丰富但研究程度较低。双庆铁矿床是该成矿带上的典型矿床,目前尚未系统开展流体包裹体及稳定同位素地球化学研究。本文通过流体包裹体显微测温和稳定同位素分析测试研究表明,该矿床自含磁铁矿石英脉到石英硫化物阶段,流体性质略有改变。均一温度变化范围为213.7℃~327.8℃,盐度变化范围为0.53%~6.14%,密度变化范围为0.703~0.888g/cm^3,属于中高温、低盐度、低密度流体; 从变化可知, 随着成矿作用继续进行,成矿均一温度与流体盐度有一定程度降低。磁铁矿的δ^18OV-SMOW 变化范围为4.4‰~10.8‰,表明磁铁矿的成矿物质来源于幔源;热液硫化物的δ^34SV-CDT 值分别为0.9‰和-0.1‰,平均值为0.4‰,具陨石硫特征,反映了火成硫和深源硫的来源特点;热液方解石的δ^13CV-PDB 变化范围为-6.3‰~-5.2‰,表明其碳质来源于深源花岗岩浆,结合δ^18OV-SMOW 的-33.8‰~-18.3‰变化范围,通过碳氧同位素研究结果推测其碳质可能主要来自花岗岩浆,后期受大气降水影响明显。石英中δD-δ^18OH2O 结果表明,双庆铁矿床早期成矿流体以岩浆热液为主, 晚期有大量大气降水的加入, 即成矿流体为岩浆水与大气降水的混合流体。
Qimantage-Dulan metallogenic belt is related to the iron copper polymetallic in Qinghai Province, which have rich mineral resources and lower research degree. Shuangqing iron deposit is a typical deposit that has not carry out geochemical research on its fluid inclusions and stable isotopes. The result of temperature measuring of fluid inclusions and the stable isotopes geochemical characteristics show that the fluid properties has changed slightly from magnetite-quartz veins stage to quartz sulfide stage. The range of homogenization temperatures is 213.7℃ to 327.8℃,the salinities of fluid are mainly in ranges between 0.53% to 6.14%,the density of the fluid vary from 0.703g/cm^3 to 0.888g/cm3,which shows that homogenization temperatures and the salinities of fluid have reduced to a certain extent during the mineralization. The δ^18OV-SMOW of the magnetite vary from 4.4‰ to 10.8‰ indicate the mineral of magnetite comes from the mantle. The δ^34SV-CDT of the hydrothermal sulfide vary from 0.9‰ to -0.1‰,the average is 0.4‰,and the meteorite sulfur characteristics of the mineral of hydrothermal sulfide reflected the characteristics of igneous source or deep origins of the sulfur. The δ^13CV-PDB of the hydrothermal calcite vary from -6.3‰ to -5.2‰ indicate its carbon from deep origins granitic magma,combining with the δ^18OV-SMOW vary from -33.8‰to -18.3‰,the carbonoxygen isotope results indicate that carbon mainly from granite magma and affected significantly by the latter atmospheric precipitation. The results of the quartz δD-δ^18OH2O shows that the early stage of the Shuangqing deposit are mainly coming from magmatic hydrothermal fluid, and the meteoric water added during the late stage, which leads oreforming fluid of magmatic water mixed with meteoric water flow.